The woody axis of flowering plants is produced by

Grafting is attempted in those plants which show:

Narrow bands of parenchymatous tissue which pass through the secondary xylem and phloem radially are called

The age of a tree can be estimated by counting the . . . . . . .

Palm is a monocotyledonous plant,yet it increases in girth. Why and how?

In old trees,the greater part of secondary xylem is dark brown and resistant to insect attack due to:
$(a)$ secretion of secondary metabolites and their deposition in the lumen of vessels.
$(b)$ deposition of organic compounds like tannins and resins in the central layers of stem.
$(c)$ deposition of suberin and aromatic substances in the outer layer of stem.
$(d)$ deposition of tannins,gum,resin and aromatic substances in the peripheral layers of stem.
$(e)$ presence of parenchyma cells,functionally active xylem elements and essential oils.
Choose the correct answer from the options given below: